Robuta

https://researchconnect.buffalo.edu/en/publications/crystal-structures-of-411-pregnadiene-320-dione-and-21-methyl-20-/ Crystal structures of 4,11-pregnadiene-3,20-dione and 21-methyl-20-oxa-4-pregnene-3,20-dione - SUNY... crystal structures pregnadiene dione methyl oxa